The present invention relates to a pressure controller. More particularly, it relates to a pressure controller which has a magnetic coil and a magnetic armature accommodated in a housing, a control piston movable in a distributor housing and actuatable by the armature, and a shaft which carries the armature and is coaxially supported in its end in axial and radial direction.
Pressure controllers of the above mentioned general type are known in the art. In a known pressure controller for controlling hydraulic pressure and acting as a magnetic valve the magnetic coil deflects the armature which in turn engages with the control piston slidable in the distributor housing so as to release or block the supply and discharge passages. Such a pressure controller is disclosed, for example in the German Auslegeschrift No. 2,255,272.
In the known pressure controllers, the armature is conventionally deflected by a rod which is arranged coaxially to the magnetic coil and supported at its ends. The support is formed in the known pressure controller by ball bearings. This makes possible a high-precision regulation, on the one hand, but requires essential manufacturing and mounting expenses, on the other hand. Moreover, such a ball-bearing supported pressure controller requires an especially expensive sealing, inasmuch as the ball bearing is especially susceptible to dirtying. Finally, in the ball bearing-supported pressure controllers, there is a special danger for axial bearings, in that they can have a one-sided running of the ball cage and, as a result, a short-time sliding friction.